The present invention relates to ball grid array packages.
Ball grid array (BGA) packages are chip-support substrates that possess a form factor change to an integrated circuit (IC) making the IC having a very high count of inputs and outputs compatible with mainstream product assembly technologies. In this respect, BGA packages are recognized as advantageous with respect to other packaging technology, in particular, for high input/output devices and high performance modules. Based on recent reports, the demand for BGAs will grow tremendously in the next several years.
The present invention provides a glass BGA (ball grid array) including a glass substrate having a plurality of conductive leads, such as thin film metal deposited thereon. A die or chip is mounted in a fixed relationship to the glass substrate, and is often mounted on the glass substrate. The die includes a plurality of I/O pads for providing electrical access to circuitry inside the die. Circuitry is included for connecting the plurality of I/O pads to the plurality of conductive leads on the glass substrate.
The die may be mounted in a recess formed in the glass substrate. Alternatively, the die may be mounted on a second substrate through a hole in the glass substrate.
A further alternative may provide a heat sink attached to the die using thermally conductive adhesives.
The entire assembly may be attached to a printed circuit board (xe2x80x9cPCBxe2x80x9d) whereby the individual conductive leads on the glass substrate are electrically connected to conductive traces on the PCB.
One advantage of the present invention is that the use of glass for the basic BGA material allows for low cost BGA fabrication.
Another advantage of the present invention is that the surface quality of glass is superior for producing thin film patterns with low defects.
Yet still another advantage of the present invention is that when glass is utilized as the BGA base material, full visual inspection of the die surface and underfill medium is available after the flip bonding and heat sink attachment.
Yet still a further advantage of the present invention is that it provides for direct heat removal from the back of the die to the heat sink and then to the board when the heat sink is mounted thereon.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.